We study Rydberg wave packets produced by pairs of time separated femtosecond laser pulses. The time separation ranges from femtosecond to picosecond time scales.
The wave packets consist predominantly of f states of principal quantum numbers n = 22-32 in Li. With a direct analysis of the field ionization spectra the n-level-resolved classical orbit times are displayed.
By chirping the second excitation pulse we demonstrate controlled amplitude oscillations of n-level amplitudes on femtosecond time scales.